


Mapping The Dungeons

by jalapeno_eye_popper



Category: Harry Potter - J. K. Rowling
Genre: Anal Sex, Canon Compliant, Dominant Snape, Inspired by Art, Legilimency (Harry Potter), M/M, Marauders Era (Harry Potter), One Shot, POV Sirius Black, Sex for Secrets, Smut, Sneaking Around, The Marauder's Map, Who Is Using Whom?, dubcon, sex potion
Language: English
Status: Completed
Published: 2020-11-20
Updated: 2020-11-20
Packaged: 2021-03-09 23:01:24
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 3,376
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/27643832
Author URL: https://archiveofourown.org/users/jalapeno_eye_popper/pseuds/jalapeno_eye_popper
Summary: During his 7th year, Sirius has an encounter in the dungeons that inspires him to hatch a plan for a more complete Marauder's Map. With a good excuse to avoid examining his own motivations, he doesn't even think to ask himself what Snape is really getting out of it.Content Warning: Explicit Dubcon Slash
Relationships: Sirius Black/Severus Snape
Comments: 2
Kudos: 33





	Mapping The Dungeons

**Author's Note:**

  * For [Francis_SinBin](https://archiveofourown.org/users/Francis_SinBin/gifts), [Draughtofpeace](https://archiveofourown.org/users/Draughtofpeace/gifts), [Jainleen](https://archiveofourown.org/users/Jainleen/gifts).
  * Inspired by [Art for fic: Mapping the Dungeons](https://archiveofourown.org/works/27643118) by [Francis_SinBin](https://archiveofourown.org/users/Francis_SinBin/pseuds/Francis_SinBin). 



Being a Marauder had a lot of perks. Fiercely loyal friends was just the tip of the iceberg. Wormtail was the acolyte. Prongs was the Old Blood brother. Moony was the peacekeeper. Padfoot was the sleaze.

Everyone knew it. He knew it himself. In a few years, no one would have any doubts that Sirius Black sold out the Potters to Voldemort.

At the moment, though, he was on a mission to gain information for the greatest Marauder secret of all: the Map. The price of this information was his body. Sex. Great sex. Surprisingly glorious, delicious sex. With, of all people, Snape.

It started a few months ago, when Snape cornered him in a part of the castle the Marauders somehow missed. It was in the dungeons, of course, the Slytherins' domain. He should have known better, but he'd been chasing tail -- there was this tasty fourth-year brunette who kept eyeing him at the quidditch pitch. If only he'd known that Snape had some dirt on this girl and used her get back at him. The Whomping Willow incident had been more than a year ago, and Snape had bided his time, waiting for the right moment.

Thus, the first time was pure humiliation, as Sirius found himself in one of the abandoned dungeon classrooms, disarmed, bent over, and tied to a desk.

If Snape had simply buggered him, that would be one thing, but this boy was becoming a master of cruelty. He made Sirius _want_ to be buggered. _Beg_ for it. Sirius could have escaped by transforming, but he didn't want to reveal that skill if he didn't have to, and from the very first touch he felt like a puppy in need of attention. With only his hands, Snape teased Sirius until he cried and used the tears in some lubricant potion that made him see stars as the head of Snape's cock slid across his prostate over and over and over...

Brilliant git.

Afterward, as Sirius lay in his dorm, unable to sleep for the sore bottom and racing thoughts, it occurred to him that he would need all his wit and charm to out-Slytherin Snape. So he schemed. He wanted a more complete Marauder's Map before they finished this final year in school. The dungeons were all that remained. He didn't tell Snape, of course, but he did loiter where he knew Snape would be, and so far had four new and interesting secret hidey holes to add to the Map. Tonight, he was going again.

Fuck, this was a bad idea. First reason: it was a secret. Hadn't told a soul. Lied, in fact, to the other Marauders about how he found these new places to add to the Map. Second reason: it was Snape. They were still at each other's throats during the day. More, in fact, and more vicious than ever. Third reason: it was distracting. He wasn't quite as brilliant, and N.E.W.T.s were coming. Revision, in fact, should have been his priority.

But gods above and below, that boy could make his body _sing_ with barely a touch, and the greasy crybaby could brew a fucking potion. The more he thought about it, the more he realized Snape hadn't been weeping in public ever since his near-death experience, so Sirius ceased calling him _Snivellus_. After shedding a few tears himself, it just didn't seem very sporting.

Of course, the way Snape tied him up wasn't exactly sporting, either.

Tonight, Sirius went deeper into the dungeons than he ever had before. He had to duck behind a suit of armor to avoid the Bloody Baron, and this put him on edge. He wanted to be found, but it was a very specific predator he was baiting. The Marauders learned long ago that Slughorn didn't seem to care what happened in his dungeons, so Sirius knew which nights he was on duty, and made a point of being there, hoping for another run-in with Snape.

He was just about to give up when he found himself disarmed and shoved through a hidden door, for the fifth time.

Yes!

Candles flared to life. A soft golden glow illuminated the dingy room, several pieces of low furniture draped with dust covers, fireplace blocked with an iron grate, and one picture window filmed with grime. Two doors on the far wall hinted at more, and Sirius figured they were in unused living quarters.

A wandpoint dug into his back. "Through there," Snape hissed, and Sirius made his feet move, one step at a time, wishing for more contact than the business end of a wand. The wait was worth it, though. The bedroom was everything the sitting room was not. Every nook and cranny was clean and dust-free. The enormous bed was covered with fresh linens. The window was spelled for diffused sunlight, even now late at night.

There was a hint of pink in that light, like a soft sunset after a rainy day cleared out, and when Sirius turned around he was struck by the way this made Snape's skin look alive and healthy, rather than deathly pale. It made him look warm, despite the perpetual cold glare. Sirius could feel his jaw going slack, and he snapped it up. He wasn't supposed to find Snape attractive, just useful.

Snape was already removing his own robes, and it took only a slight sneer for Sirius to get to work doing the same. He stripped himself, as he always did after the first time. He suspected that even waving a wand to vanish the clothes would be too personal for Snape, too much of a _service_ in this twisted little power game. In fact, Snape normally kept on his clothes, at least until Sirius was bent over and unable to look. Then Sirius wouldn't see Snape at all until he was finished, fully composed, and came around to look him in the eyes, as if to gloat before releasing him and quietly slipping away.

Now, he could see that Snape's underpants had an upgrade since the last time he had a chance to notice. Black silk, like his own. He narrowed his eyes, wondering at the custom tailoring of Snape's shirt as each button was undone. Sirius flicked his eyes to the growing pile of clothes on the floor and then back to Snape, who was tossing aside the last garment and raising one eyebrow at Sirius' delay. He hastily finished, and then met Snape's eyes again, wondering who would have paid for the improved wardrobe. The subtle elegance of it smacked of pureblood _Old Money_ rather than the poor son of a muggle Sirius knew him to be.

That raised eyebrow changed direction, narrowing as his lips turned down to a deep frown, and Snape spat, "I have a new patron, and he wants me to finish testing this potion."

Sirius was a bit rattled. Had Snape known exactly what he was thinking?

Snape produced a vial, the same glass and stopper and crystal clear lubricant they'd used four times already. Sirius trembled. He had suspected he'd be reduced to tears again, but he hadn't known he was being used at least as coldly as he tried to tell himself he was using Snape.

Already blinking away a fresh batch of those salty drops, Sirius turned to lean over the bed, stretching his arms, ready for the ropes.

He heard Snape hiss, "Bloody idiot," and then come up behind to press against his backside. Sirius felt one hand creep around his waist, run fingers through his pubic hair, and then firmly grip his swelling cock. He gasped and made fists in the sheets, back arching to push his bum against Snape's growing hardness. Snape slowly stroked him to a full erection as he spoke, "The first trials are a success, but you should know that any potion with a person's secretions can vary widely. The other trials were yours. This one is mine."

It took Sirius a minute to understand what Snape had said, and in the space of that minute, Snape twisted him around and shoved him onto the bed. Sirius sprawled on his back, hands at his sides and knees bent high, shivering as he looked up at the ceiling. Snape was using him to invent a new potion... a potion that required inducing tears to make it... and a good deep dicking to test it. That made enough sense, in the way that sometimes you have to accept how magic is not always unicorn tails and levitating feathers. Snape using his own tears for another trial might have even made sense, just like he said, for more thorough testing. But, this feeling of admiration welling up inside Sirius did _not_ make any sense.

He was somehow _proud_ of the greasy git.

Snape crawled up onto the bed as well, and Sirius swallowed hard, unable to tear his eyes away now that he was finally getting a proper look at that cock, bewitched at the visible swelling and darkening. Without a word, Snape uncorked the vial and poured it into his left palm. Entranced, Sirius could only watch as Snape gazed at his own hand, studying his reaction with steady, dark eyes. The only betrayal of his feeling was the slight parting of his lips and his hardening penis lifting higher and higher. Sirius was painfully hard now, himself.

Finally, Snape shifted his eyes to Sirius, narrowing them slightly. Caught staring, Sirius could feel the heat in his cheeks, but he couldn't look away. After a few seconds of eye contact, Snape rolled his in annoyance and threw a leg over Sirius, straddling his stomach. He reached back and grasped Sirius with the lubricated hand, and Sirius gasped, balls tightening and blood rushing in his ears.

"Do contain yourself," Snape drawled.

"Not a chance," Sirius replied, reaching up to bury one hand in Snape's hair, thumb trailing along his jaw. Snape glared but did not let go, and Sirius ran his hand down Snape's neck and to his shoulder, gripping hard. With his other hand, Sirius crept along the sheets until he hit Snape's knee and this slid up his thigh.

With his free hand, Snape swatted him, and Sirius retreated, resting his curious fingers at the back of Snape's knee.

Face impassive, Snape seemed inclined to allow this for how he had to brace one hand on Sirius' toned chest for what came next. Snape tilted his hips and pressed the tip of Sirius' erection against his tight bum, sliding the slick organ around his hole. This also pressed his balls to Sirius' stomach. "Ah," he gasped, overwhelmed by all this skin he'd never before had a chance to touch.

He almost missed Snape's slight "Ah," that mirrored his as Snape sank down.

Watching Snape's face was a lesson in frustration. Sirius wanted to hit him, to break through that stony facade, but he knew that if he fought back he'd be tied up again. He couldn't risk that. Now that he got his hands on Snape's lean, hard body, he wasn't letting go.

Feeling Snape's insides was a lesson in control. The cold, hard surface of him gave way to a hot, silky grip on Sirius' cock, and he gasped again as Snape took his time shifting his angle and depth to get it just right. Snape's impossibly dark eyes fluttered closed, and Sirius couldn't hold back any longer, lifting his hips to drive a little deeper.

Snape growled with a depth that promised the imminent development of a downright sinful voice, and he opened his eyes with a glare. He leaned down, and Sirius shivered with anticipation as Snape slipped his hand from Sirius' chest up past his shoulder to brace on the bed and brought the other hand to his neck.

Sirius didn't need to be tied up to feel pinned. He was at Snape's mercy. And he wanted to be.

He _wanted_ him.

Snape's eyes rolled up, breaking contact again, and Sirius couldn't tell if it was an expression of pleasure or annoyance. Sirius felt like fire, itching for more contact, more movement, more, more. He gripped harder on Snape's shoulder trying to pull him down. His stomach did a flip when he realized he wanted a kiss.

But Snape didn't allow it, squeezing Sirius at the throat until he stilled completely. Sirius tilted his chin up, an instinct to open the airway, and Snape's grip loosened. Opening his mouth for a deeper breath, Sirius let his jaw hang open as he panted. Snape used his thumb to stroke the vulnerable flesh and then came to a rest just under Sirius' chin. Tilting his own chin up and away, Snape let out one ragged breath. Then he moved his hips, slowly tilting back and forth, and Sirius groaned at the tight friction.

Snape glared again and hissed, "Don't you fucking _dare_ come before me."

Sirius whimpered, sure he would explode if Snape kept talking. He hadn't said much before, simply focusing as he worked over Sirius' body with his hands. Did he know that his voice could melt steel, even as it made Sirius that much harder? Panting, Sirius pulled him a little closer in between each exhaled breath, "Then -- you -- better -- come -- soon."

Picking up the pace, Snape switched to more of a rocking motion, and Sirius gasped a bit louder with each _thud_ of Snape's cock coming down against his stomach as the same time his own cock was engulfed by a furnace of a man. The firm strokes of that arse on his shaft lit up every nerve ending of his body, and his pulse fluttered against the fingers at his neck.

Sirius slowly slid his arm further around Snape's shoulders, and his other hand slowly up his thigh. Finally, Snape gave a clue like he might be enjoying himself instead of performing some necessary evil, and the tiny shudders of wiry muscles under his hands made Sirius tremble with need.

He looked up to Snape's face but maybe wished he hadn't. Snape's eyes were unfocused not in lust but in deep thought. His mouth was parted but baring his teeth in a scowl. His hair fell down in waves but not close enough to brush against him.

Even so, Snape sped up his movements, grimaced in some expression of completion, pelvic floor clenching around Sirius and making him shout, "Oh!"

As Snape spurted hot cum over Sirius' stomach and chest, Sirius closed his eyes, bit his lip to keep from shouting again, flexed his hips, and came as well, pushing harder into Snape's tight arse and holding on for dear life.

The endorphins crested, then started to fall, and Sirius cried out in overstimulated pain as Snape wrenched himself away and landed heavily on the bed next to him. As he bucked his hips one last time, he could hear Snape cast a mumbled charm, presumably to clean up, and then tilted his head to see what Snape would do next. Laying on the bed, panting, he watched Snape roll over the edge onto his feet and began putting his high-quality new clothes back on.

Snape's face was a blank mask again, his appearance fully put together, and his bearing totally in control. No one would have been able to tell he just rode another man to a blinding orgasm. As he slipped his robes over his shoulders, Snape said, "Do not come back to the dungeons at night."

Sirius sucked in a deep, steadying breath, and then he frowned and sat up, reaching for his underpants. Trying to play it cool, he simply asked, "Why not?"

"I won't be waiting."

"What makes you think --"

"Don't be a moron, Black." Snape pinched the bridge of his nose, and Sirius had the mad urge to drop a kiss on the tip of that excessive beak. He gave himself a mental shake so he could pay attention when Snape continued, "The others leave you alone because they know I wanted my revenge. They know I've had it now, at least twice, so it's no longer my turn. The potion tests are done, so I have no reason to insist otherwise."

Gutted, Sirius didn't know what to be most upset about. The insult to his intelligence? The bizarre Slytherin honor code? The threat of unspecified _others_ who wanted a turn to attack him? None of that was as brutal as the knowledge that Snape's interest was protecting him, and that interest was about to dry up as quickly as the cum matting his chest hair.

Shuddering and choking back a sob, Sirius whispered, "Maybe you could --"

Snape scowled. "Shut up, Black. I got what I wanted. There is nothing I wish to do for you, even if I could." 

"You have to," Sirius said quickly, wracking his brain for all the contingencies he had thought of between their first and second meetings, and then promptly forgotten in favor of thinking with his dick.

Pinning Sirius with an icy glare, Snape twisted a palm up in a gesture of impatient expectation.

Sirius gulped, unwilling to look too closely at why he felt like crying this time. It was too hard to think while naked and desperate. What kind of threats did Sirius still have in his back pocket? He lowered his voice and glared as he said, "You'll keep meeting me in secret, or I'll go public. _Watch your bums! Snivellus finally cried into one of his potions and it made him gay as a parade and randy as a puffskein!_ My gossip network is so good, I can plant four different clues with four different people, and then I won't even have to say it myself. The timing --"

Snape flicked his wand and silenced him with a nonverbal hex.

In mute outrage, Sirius moved to stand, but the ropes came next, pulling his wrists out away from his sides and forcing him to kneel on the bed.

Staring at his wand as he twirled it in his long fingers, Snape asked, a little too calmly, "Do you know what Legilimency is?"

No way. He couldn't do that... Could he? Sirius thought back to how he had wondered about Snape knowing exactly what was on his mind earlier tonight. His jaw dropped again, not in pleasure but in surprised horror. He wanted to know, but literally could not ask, how much practice Snape had in that skill. Mind magic was a dangerous violation of another person, even more alarming than the physical attacks. Physically, Sirius understood his body's responses to the games he and Snape were playing. The mental and emotional responses were much more difficult and frightening to consider.

"If I were you I'd be very careful about what sorts of secrets you wish to spread as rumor. After so many opportunities to read you during your totally unguarded, post-orgasmic bliss, I have found more than enough to make you regret anything other than total silence." Snape more securely gripped his wand and sneered. "Do not prove you are an idiot by thinking that any rumors about my dedication to inventing new potions would hurt me." 

Then Snape cast a _finite_ to undo the bindings and returned Sirius' wand to him with a perfect parabolic toss. He quietly slipped away while Sirius fumbled the catch.

Sitting alone and staring at the rumpled bed, Sirius already felt full of regret. For several minutes, he didn't even bother with the counter-hex that would allow him to speak again, as he was very sure he could never tell a soul what happened here. With no way to know exactly what Snape had seen of Sirius' sleazy antics, he could not even risk putting this room on the Marauder's Map.

\----------

~End Notes~

This fic was made possible by the people and discussions at The Black Prince server <https://discord.gg/At9FwGB>. Specifically, I was inspired by watching [Francis_SinBin](https://archiveofourown.org/users/Francis_SinBin) draw NSFW art (below) on livestream, fixed up the ending thanks to [Jainleen](https://archiveofourown.org/users/Jainleen)'s beta work, and had a fellow Snack newbie [Draughtofpeace](https://archiveofourown.org/users/Draughtofpeace) to sail this ship alongside me. Thank you, everyone!

\----------

Like the art? [Drop kudos at the works page for it!](https://archiveofourown.org/works/27643118#feedback)

**Works inspired by this one:**

  * [Art for fic: Mapping the Dungeons](https://archiveofourown.org/works/27643118) by [Francis_SinBin](https://archiveofourown.org/users/Francis_SinBin/pseuds/Francis_SinBin)




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